The following work presents a generally applicable model for the prediction of the separation efficiency of random packing of different shape with size between 8 and 90 mm for gas-liquid systems in the entire operating range up to the flooding point. The new model was derived on the basis of the droplet flow model and that mass transfer in the gas phase occurs between continuous gas phase and the swarm of droplets falling down in packed bed. The new model was validated with about 5000 experimental distillation, absorption and desorption data of ENVIMAC data bank (EDB) in a very wide range of changing operational and constructive parameters; from low top pressure of 13 mbar up to 2 bar. Satisfactory consistency for practical application was found between experimental values of the separation efficiency for about 115 different types of random packings and calculated values based on the new model. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.